The aim of this project was to clarify the effectiveness of pavement maintenance (preservation) activities, in the form of periodic maintenance and rehabilitation, on pavement condition and distress (roughness, rutting and cracking) deterioration rates. This was addressed by estimating trends in pavement deterioration in three jurisdictions (New South Wales, Queensland and Victoria) from a time series of observational data (supplied by the jurisdictions) using mostly iPave condition and deflection data. In order to assess the effectiveness of the various pavement maintenance treatments, a comparison of these observational trends with historical and predicted rates of deterioration was made.

The main findings of the study were as follows:

A comparison between the observed deterioration rates derived from the time series of observational data with historically-derived rates and the Austroads RD model estimates suggested that the three approaches produced comparable results in terms of roughness and rutting deterioration, but not for cracking.

Based on the historical rates of roughness and rutting deterioration representing pre-treatment deterioration, the post-treatment roughness deterioration rates in NSW and Victoria were reduced by a range of between 8% (seals) and 58% (OGA), demonstrating the effectiveness of the surface treatments.

Comparisons of functional condition parameters (roughness, rutting and cracking) against the mean maximum deflection found that their deterioration rates were significantly influenced by pavement strength. The effect of traffic and climate on deterioration was not as strong as pavement strength.